Adenosine as an adjunct to inducing rapid asystole during cardioplegic arrest.

A study was undertaken in 68 patients to assess the beneficial effect of adenosine as an adjunct to K(+)-enriched cardioplegia to induce rapid asystole. In the study group (n = 22), adenosine was given in the dose of 3 mg bolus into the aortic root immediately after aortic cross clamp along with K(+)-enriched cardioplegia. In the control group (n = 46) K(+)-enriched cardioplegia solution was used without adenosine. Important parameters monitored were: time to asystole in seconds and recovery of normal sinus rhythm following release of aortic cross clamp. In addition, standard haemodynamic parameters were measured. The results showed a marked reduction in the time to achieve asystole in the study group (3.53 +/- 1.18 seconds) as compared to the control group (18.19 +/- 11.80 seconds) (p < 0.001). Restoration of sinus rhythm was achieved in the study group at 43.53 +/- 33.60 seconds while in the control group it was achieved at 161.90 +/- 11.36 seconds (p < 0.001). The haemodynamic parameters measured 10 minutes after the termination of cardiopulmonary bypass were not different in the two groups. When measured one hour after the termination of cardiopulmonary bypass, haemodynamic parameters in the study group revealed a statistically significant improvement in inotropicity. No side effects or complications were encountered in the study group. We conclude that adenosine given as an adjunct to K(+)-enriched cardioplegia helps to achieve rapid asystole and faster recovery of sinus rhythm with no adverse effects and may aid in better myocardial preservation.

Effects of intranasal challenge with group A beta haemolytic streptococcus M type 49 in Swiss albino mice.

Mice are susceptible to natural infections with streptococci and therefore can serve as suitable animal models to study experimental streptococcal infections. In an earlier study, we had shown the development of pharyngeal colonization, antibody response and histopathological changes in the heart following intranasal (IN) challenge with a rheumatogenic serotype of group A beta haemolytic streptococcus, the M type 18. To determine if nonpharyngitis associated serotypes can also elicit similar responses, 30 Swiss albino mice were challenged intranasally with 2 x 10(7) colony forming units of a skin associated serotype of group A beta haemolytic streptococcus, the M type 49. Pharyngeal colonization varied from 64% (n = 30) in the first week to 69% (n = 16) during the fourth week after IN challenge. Eleven (36.7%) of the 30 animals studied showed antibody response to DNase B (ADNB) with peak titers varying from 150 to 1200 units. Wide variations were seen in ADNB titers in individual mice. Histopathological evidence for cardiac lesions were seen in three animals. The changes were mild and varied from mild to chronic endocardial inflammation to calcification. The study shows that Swiss albino mice are also susceptible to IN challenge with skin associated strains of GABHS and therefore can serve as useful models to study the effects of experimental infection with diverse serotypes of GABHS.

Rheumatic fever chemoprophylaxis in adults.

In 2340 adult patients above the age of 26 years with rheumatic valvular disease (RHD) seen since 1987, injection benzathine penicillin (once in 3 weeks) was discontinued and the patients were followed for evidence of rheumatic fever for a period of one to nine years (mean of 3 years). Recurrence of rheumatic fever was seen in 5 patients (0.21%). This study confirms that recurrence of rheumatic fever in patients with RHD above 26 years of age is very low and hence we recommend long term chemoprophylaxis to the patients above the age of 26 on an individual basis.

Pharyngeal colonisation, ADNB response and development of cardiac lesions in mice following intranasal inoculation with group A beta haemolytic streptococcus M type 18.

Swiss albino mice from a randomly bred colony were inoculated intranasally with 1.6, 2 or 2.4 x 10(7) colony forming units of a mid-logarithmic phase culture of group A beta haemolytic streptococcus M type 18 for 3 days, 6 days or once a week respectively for three weeks. Pharyngeal colonisation could be observed in 67 (59.8%) of 112 mice on 4th day after inoculation and 14 (38%) of the 37 mice on 21st day. Out of 27 mice tested for determination of antibodies to deoxyribonuclease B at regular intervals for 98 days, 15 (55.5%) showed responses, with maximum titers varying from 50 units to 4800 units in individual mice. Histopathological evidence for cardiac lesions were seen in five (3.03%) of the 165 animals studied. These included one case of severe endocarditis, two cases of endocarditis with valvular lesions and one case with non-specific lymphocyte infiltration in the heart. One other animal showed subendocardial oval nodular aggregates. Although the cellular nature of these lesions were not determined, this study shows that Swiss albino mice can serve as suitable animal models to study experimental streptococcal infections. However these are preliminary observations and are to be confirmed and revalidated by further controlled experiments.

Exercise capacity in untrained normal adults: a nomogram for Indians.

The exercise capacity of 155 hospital-based patients (125 males and 30 females) who underwent treadmill testing and coronary angiography for investigation of chest pain was used to derive regression equations for exercise capacity (METS) against age. A regression equation [18 - 0.16 x (age)] for males and [11 - 0.84 x (age)] for females was obtained. Using these equations an exercise capacity nomogram was developed. From this nomogram the predicted exercise capacity was calculated for another set of 228 patients (209 males and 19 females) whose treadmill tests were negative. The results confirmed that the nomogram could be applied to determine the expected and actual exercise capacity of Indians within a mean difference of 0.08 METS. This nomogram is being offered for clinical, therapeutic and preventive use for Indian patients.

Coronary angiographic findings in patients with diabetes: an exercise in cardiovascular epidemiology.

A study of 516 patients with diabetes mellitus who presented with chest pain and an equal number of matched controls without diabetes examined by selective coronary arteriography was undertaken. Detailed analysis of the angiograms showed that prevalence of CAD in diabetics with symptoms was 86.6%. This prevalence increased with age. Multivessel disease was more common in diabetics that in controls (p < 0.01). In diabetic patients disease involvement of proximal and distal segments in the same vessel was more common (p < 0.01). The Gensini score of quantitative expression of severity of CAD was higher in diabetics (p < 0.05). The number of occluded segments in the coronary tree was higher in diabetics (p < 0.01). No correlation could be established between severity of disease and age, body mass index or duration of diabetes. It is concluded that diabetes affects the coronary arteries of Indian patients more adversely than those of non-diabetics. The prevalence of CAD among diabetics increases linearly with age.

Plasma insulin levels in coronary artery disease.

Seventy two consecutive patients without a history of diabetes and normal fasting plasma glucose were included in this study of insulin levels. Standard oral glucose tolerance test with 75 gm glucose and fasting and two hour insulin levels were estimated in all patients. Coronary artery disease (CAD) was confirmed or excluded by selective coronary arteriography. In 20 patients, CAD was diagnosed by electrocardiographic (ECG) and clinical evidence of earlier myocardial infarction. Mean fasting plasma insulin was 31.40 +/- 22.2 IU/dl in the CAD positive and 32.3 +/- 13.6 IU/dl in the CAD negative group. The mean two hour plasma insulin was 274.6 +/- 301.1 IU/dl in the CAD positive and 104.8 +/- 74.9 IU/dl in the CAD negative group (p < 0.04). Two hour plasma insulin levels were significantly higher in patients with atherosclerotic coronary artery disease. It is concluded that the estimation of a two hour plasma insulin level after 75 gm of glucose load, could help differentiate CAD from normals.

Distribution of Body Mass Index in Indian patients with coronary artery disease.

To study the distribution of overweight and obesity among Indian patients with coronary artery disease (CAD), a cross-sectional analysis of computerized data on patients, proved to have CAD by selected coronary arteriography, was carried out. There were 1078 patients, with 1052 males (mean age +/- SD:50 +/- 7.5) and 26 females (mean age +/- SD:47.7 +/- 8). Of these, 22 percent had single vessel disease, 38 percent two vessel and 40 percent three vessel disease. The Body Mass Index (BMI) was calculated from the height and weight data. BMI over 27 kg/m2 was defined as overweight and that over 30 kg/m2 as obese. Data analysis revealed that only 8.2 percent of patients with CAD were overweight, of whom 2.2 percent were obese. CAD was seen in Indians with BMI from 15 kg/m2 onwards. The BMI in the risk factor groups of smoking, diabetes and hypertension was not different when compared to those without the risk factors. However, the BMI was higher in those with a positive family history (p < 0.01). BMI was higher in the businessmen and executives but did not qualify for overweight or obesity group. BMI did not correlate with the various lipid fractions studied. It is concluded, that in Indian patients, angiographically proved coronary artery disease can be seen with low BMI.

Intracardiac blood flow velocities and cardiac output in normal fetuses: a prospective pulsed Doppler echocardiographic study.

Two dimensional and pulsed Doppler echocardiographic studies were performed in human fetuses with the aim to establish normal values for blood flow velocities and cardiac output in Indian subjects. Thirteen pregnant mothers were prospectively followed up at 4 weeks interval from 19 to 40 weeks of gestation. Blood flow velocity spectra across aortic, pulmonary, mitral and tricuspid valves were analyzed to obtain peak flow velocity (cm/sec) and velocity time integral. Aortic and pulmonary diameters were measured at the valve level from two dimensional echocardiographic images and ventricular stroke volume calculated. The values were plotted against fetal age (weeks) and fetal weight (gms). Our results showed that there is a linear increase of the measured Doppler data, with increasing gestational age and weight. These values may be used as a reference for the Indian population.

Sizing of balloons in balloon mitral valvotomy.

In twenty six consecutive patients who underwent balloon mitral valvotomy (BMV) by the transseptal double balloon technique, the mitral valve area (MVA) increased from 0.78 +/- 0.1 cm2 to 1.80 +/- 0.3 cm2, (p < 0.001). Effective balloon dilating area (EBDA) of each combination of balloons used was calculated using a standard formula. Patients were classified into 4 subgroups with approximate EBDAs of 3.3, 4.0, 4.9 and 5.7 cm2 and they had mean post-BMV MVAs of 1.28, 1.78, 1.89 and 1.98 cm2 respectively (ANOVA F = 3.32, p < 0.05). Patients were reclassified after normalisation of EBDA and post-BMV MVA to square metre of body surface area. Three subgroups with mean normalised EBDAs of 2.32, 2.96 and 3.62 cm2/m2 had mean normalised post-BMV MVAs of 0.99, 1.17 and 1.40 cm2/m2 respectively (ANOVA F = 6.85, p 0.01). A trend towards increasing mitral regurgitation with increasing balloon size was noted. Three cases of mitral regurgitation including one case of severe mitral regurgitation occurred in the subgroup of 9 patients with largest normalised EBDAs. The overall correlation between normalised EBDAs and normalised post BMV MVA was strong r = 0.67, p < 0.01). The optimal normalised EBDA for Indian patients undergoing BMV is around 3.6 cm2/m2. Balloons used should be sized accordingly.

Assessment of impaired left ventricular diastolic function in patients with coronary artery disease, using radionuclide angiography.

Left ventricular (LV) diastolic filling at rest was assessed in 76 patients with coronary artery disease (CAD) and 16 healthy subjects using radionuclide angiography. Peak LV filling rate (PFR), expressed in end diastolic volume per second (EDV/sec), was subnormal in CAD patients (1.95 +/- 0.51 as compared to the normal 3.11 +/- 0.36, P < 0.001) and time to PFR (TPFR) was prolonged (171.1 +/- 79 msec versus 106.6 +/- 25 msec normal, P < 0.001). These indices were also abnormal in 60 patients with normal resting LV ejection fraction (PFR 2.17 +/- 0.48 EDV/sec, TPFR 163.9 +/- 68 msec). Abnormal LV filling at rest (PFR EDV/sec or TPFR 160 msec) was found in 88 percent of all patients with CAD, 85 percent of patients with normal resting LV ejection fraction, and 83 percent of patients without Q waves on resting electrocardiogram. Thus, LV diastolic filling, evaluated non invasively by radionuclide angiography, appears to be abnormal in a high percentage of patients with CAD independent of LV systolic function or previous myocardial infarction.

Assessment of left ventricular diastolic function in young diabetics--a two dimensional echo Doppler study.

Left ventricular diastolic function was assessed in 21 young diabetic subjects (less than 35 years) by Doppler transmitral flow velocity examination and compared with an equal number of matched controls. Diabetic subjects had higher heart rates (89 +/- 2 vs 79 +/- 4 beats/minute, p less than 0.015), peak late diastolic (A) velocity and a velocity time integral (56.6 +/- 13.4 vs 45.3 +/- 11.4 cm/sec. p less than 0.005 and 7.3 +/- 5.2 vs 6.5 +/- 2.5 cm p less than 0.03 respectively) and total transmitral flow velocity integral (25.8 +/- 5 vs 22 +/- 3.2 cm, p less than 0.05). Peak E velocities, E velocity time integrals, E/A ratio, and peak filling rates were similar in two groups (p = not significant). These data suggests that young patients with diabetes mellitus have normal left ventricular diastolic function. The minor transmitral flow abnormalities are possibly due to autonomic dysfunction, e.g. increased sympathetic activity resulting in increased heart rate and cardiac output.

Tetralogy of Fallot with absent pulmonary valve: diagnostic features and management.

Tetralogy of Fallot with absent pulmonary valve is a rare congenital malformation. The diagnostic features and surgical management in ten patients with this malformation have been described. There were five male and five female patients, (age 3 1/2 to 26 years). The common symptoms were recurrent respiratory tract infection and cyanosis. Examination revealed hyperdynamic precordial pulsations, single second heart sound and an early diastolic murmur along the left sternal border in all. Electrocardiograms were indistinguishable from typical tetralogy of Fallot. Chest X-ray revealed cardiomegaly, prominent pulmonary conus and dilated pulmonary arteries in all cases, lung vascularity being variable. Echocardiographic findings were diagnostic and are discussed in detail. Cardiac catheterization and angiocardiography revealed annular stenosis in all, along with aneurysmal dilatation of main and branch pulmonary arteries. Eight patients underwent intracardiac repair. There was no perioperative mortality. All patients have been followed up for 350 months (mean 29 months).

Phase analysis of radionuclide ventriculograms in patients with coronary artery disease.

Phase analysis of radionuclide ventriculograms were performed in eighty patients with coronary artery disease (CAD) and in sixteen healthy subjects. The phase image in the normal group revealed a homogeneous pattern and a narrow bell shaped histogram. In forty one patients with CAD whose Left ventriculogram showed hypokinetic segments, phase image was abnormal in twenty six revealing well demarcated areas of contraction abnormality and a histogram showing broad base with multiple peaks. The mean phase angle and the standard deviation (S.D.) of phase histogram of the abnormal segments was significantly different from normal. Eighteen patients with CAD had akinetic segments. Phase analysis was abnormal in all. Six patients with CAD had dyskinetic segments. It is concluded that phase image analysis is very useful in detecting segmental wall motion abnormalities.